geol 452/552 gis for geoscientists i -...
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GEOL 452/552 -
GIS for Geoscientists I
Lecture 7
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Lecture Plan
• Projections & coordinate systems intro
• Map design process
• Use of colors
• Ch 3 tutorial (skip labeling parts)
• HW4: census data maps + “poster”
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Projections - mini introHow to
get a point from a sphere
“map” ...
(Note line crossings!)
... to a planar map (paper, screen)
Hey GPS, what Latitude/
Longitude am I on?
20.44395, 45.23432
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Coordinate System/Projection
• All points on a sphere are measured in angles (Latitude (N-S), Longitude (E-W)
• 42.314572 degr. North, 83.054021 degr. West
• How to plot points (polygons) on a flat (paper) map?
• A) Unprojected (“GCS”) - no translation*
• But: some distortion everywhere (Greenland)
• B) use a Projection:*
• Translate Latitude/longitude angles (degrees) to distances (meters)
• Aim: manage distortion: low in “center”, bad at “fringe”
• Projection: integral to drawing (and making) maps
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Map Design Process• Determine the objectives of the map (user,
audience, goals, “story”)
• Include which data layers (for the objective)?
• (Perform analysis - creates additional layers)
• Choose colors and symbols for layers (“visualize”).
• Add map elements (north arrow, scale text, scale
bar, legend, ...), text and images
• Plan a layout for all elements (where on paper?)
• print or make pdf/jpg (File - export map)
• let’s look a some examples of maps
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www.neatline.net/Pictures/cartography.html
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www.neatline.net/projects.html
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Choosing layers and data frames
• Be selective about the amount of information
• Too many layers: visual clutter!
• Have the important elements stand out (color, size)
• Spread different layers over different data frames:
• Tell a story: Here’s the overall situation (Frame A), here’s the problem (Frame B), here’s a solution (Fr. C), etc.
• Provide spatial (geographic) context: (show roads, zoom-in from big-picture, schematics)
• Add lat/long, UTM grids if coordinates must be looked up
• Do not make the reader work needlessly!
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comparethese two maps:
•Better
contrast
•High values:
different
symbol colors
(green)
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• Use “round” map scale (:24,000 not 1:23,766)
• Add map elements: title, legend, north arrow, scale info, scale
bars, grid(s), coordinate system info, author, date
• Use clear layer names (attributes) in legend:
Population in 1990 not just POP90 (pop vs soda? pop music?)
• Use nice value ranges: 100 -120 not 102 -123
• Add charts, images and text to support your story
• Aim for even distribution of all map elements
Scales, map elements
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Basic principles for balance
• (Disclaimer: I’m not really a graphics designer!)
• Balance elements on the page:
• aim for a even distribution (visually pleasant)
• avoid cluttered areas
• manage blank areas (empty or “negative” space)
• Align straight edges (data frames, text boxes, images)
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Visualize empty space
from: Designing
better Maps
(Cynthia Brewer)
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Earth as negative space:
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Text
Visualize Tight spaces
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Neatlines (boxes): help to convey the visual structure
Poor design
Better design
Neatlines
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www.neatline.net/projects.html
? Space between elements, neatline boxes, alignments along edges ?
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http://www.neatline.net/projects.html
Note: space between elements, neatline boxes, alignments along edges
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Copyright © 2009 by Maribeth H. Price
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Crowded
Unclear name
Abbreviations
, to format large numbers
Some tips on making better Legends
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Choosing colors and symbols
• Natural earth tones usually look better than clashing (loud, obtrusive) colors (exception: emphasis!)
• Mimic nature tones, such as using blue to represent water
• Use pastels or subdued colors for most of the map; use bold colors only for emphasis
• Make ramps easy to understand (single “main” color)
• Apply emphasis with color, size, and thickness
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Pastels and natural colors
(light-dark) color ramp to indicate increasing population
Grid with subtle color
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Color choice - what does the map need to communicate?
Natural: Which polygon is water?
Distributions: Where is rainfall higher?Which towns have more people?
Simple Overview
Hi-light: Where’s the danger?21
Tips for map making in layout view
• You can copy & paste from power point (textboxes, images, boxes, arrows) - make a group!
• make data frames a good size (properties - Size)
• in layout mode: use zoom to set you approx. scale, the set to a “round” fixed scale
• Layout mode: Copy and paste data frames graphically
• Use guide (blue lines) to dock and line up the data frames
• use a 0.5 - 1 inch distance to paper end
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Color Brewer: www.personal.psu.edu/cab38/ColorBrewer/ColorBrewer.html
WebCT: Link in GIS Materials Folder
Book: Designing Better Maps: A Guide for GIS Users (Cynthia A. Brewer, ESRI Press, 2005)
C. Brewer: Basic Mapping Principles for Visualizing Cancer Data Using GIS, American Journal of Preventive Medicine, Volume 30, Issue 2
on WebCT: GIS Material folder
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Lab part• Ch 3, tutorial:
• Must-do parts: (->): 1-10, 22-47
• More on labeling: 11 - 2, optional
• HW 4: Mini-project 1 (Due next week)
• Data in Geol552\data\mini_proj_1_data folder
• Start reading the instructions (7 Tasks)
• Tasks 1 - 6: start on third page of ArcUser “Mapping census 2000” article (“start here”)
• Good color pdfs on WebCt (miniproj 1 folder) and in delphi data folder
• Task 7: make your own two frame map
10,000,000 to 33,880,000
5,000,000 to 9,999,999
1,000,000 to 4,999,999
493,782 to 999,999
Number of People, 2000
Number of peopleby state
Number of peopleby county
500,000 to 9,520,000
100,000 to 499,999
50,000 to 99,999
25,000 to 49,999
10,000 to 24,999
67 to 9,999
Data Source: U.S. Census Bureau, Census 2000Redistricting Data (PL 94-171) Summary File.Cartography: Population Division, U.S. Census Bureau.American FactFinder at factfinder.census.gov provides census data and mapping tools.
0 100 Miles0 100 Miles0 100 Miles
0 100 Miles
Mapping Census 2000: The Geography of U.S. Diversity 15U.S. Census Bureau
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• Note: this (my) poster shows the basic layout
• BUT: it’s pretty shoddy - please improve!
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